Fluid-operated braking system



May 20, 1924. 1 1,494,569

s. E. ALLEY FLUID OPERATED BRAKING SYSTEM Filed Nov. ze.. 1923 2 shears-sneer 1 ,f l 55 I I I z5 ,I i i 18 1 l I H 15 14' l I l H 1,7 IHtl Z3 IL JI 16 .Nm

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D I 'd ,l V/*fz 1Q f E Z0 l( 4/ [I W @fyfmvM 1,494,569 5.5. ALLEY FLUID OPERATED BRAKIG SYSTEM Muay 20, 1924.

Filed Nov. 2e 1923 2 sheen-shun 2 Patented may Z0, 1924. i I

s'rATEs waste s'rErmNEvANs ALLEY, or wEsTMINsTEn, LoNDoN, ENGLAND, AssIGNon 'ro 'mn SENTINEL" WAGeoN wonxs (1920)` LIMITED, or WDSTMINSTER, LONDON, nne- LAND, A BRITISH COMPANY.

lIEIlaUII)-OEERA'IPE]VJ BRAKING SYSTEM.

Application led Novemberr 26, 1923. Serial No. 677,122.

To all whom z't may concern:

Be it knownthat I, STEPHEN EvANs AL- LEY, a subject of the King of England, re-

siding at Westminster, London, England,

ton, a face of which first-named piston-mem-` m ber is exposed to the vacuum in the system when braking is taking place and the opposite face of which is accessible to the atmosphere. ln this way the vacuum in the braking system will exert a pull upon the piston-member and give a reaction to the op- 'erators control-element corresponding in intensity to the force being appliedl to the4 main braking piston. rlhe operator' will thus receive an indication' of this last-named force and be enabled to graduate it. veniently the said piston-member coupled to the operators control-element serves as the valve for controllingcommunication 'between the mainbraking piston and the means creatingA the vacuum, thus simplifying and increasing the safety of the system. Y

According to another feature of the invention there is provided a vacuum braking vvsystem comprising the combination with a 'source of pressure, an eJector, and a conduit leading to the main braking piston, from which conduit air can be exhausted by the ejector, of'an operators control-element for .the system, and piston-member, other than the main braking piston, directly coupled to the said control-element, which piston-mem-r` ber Acontrols communication between the source of pressure and the ejector, and'between the ejector andthe braking system, and has,for the purpose already ind1cated, one face exposed to the vacuum in the sys- Contem when braking is taking place and the opposite face accessible to the atmosphere. There is thus provided a simple and compact arrangement fof, controlling mechanism for the. system in which the parts vto be manipulated' by the operator are reduced to the minimum. A

Preferably thereis combined with the piston-member coupled to the operators oontrol-element, a venting valve for destroying the vacuum in the braking system, which valve is opened by the said piston-member when the latter reaches the position it occupies when braking is not. taking place. When this venting valve is provided, it will be found advantageous to have the parts so arrangedthat the piston member in returning to the position it occupies when braking is not taking place first shuts olf communication betweenv the main braking piston and the means creating the vacuum, and subsequently destroys the vacuum in the braking system.

For a more complete understanding of the invention there will now be described, by

way of .example only and with reference to the accompanying drawings, one constructional form of controlling mechanism for a vacuum braking system accordingto the invention. It is to beunderstood, however, that the invention is not limited to the precise constructional details set forth.

ln these drawings l Figure 1 is a side elevation partly in section of the mechanism;

Figure 2 is a section on the line 2-2 o f Filgure 11, and

i re 3 is a ped v Like reference numerals indicate like parts throughout the drawings.

The construction illustrated comprises a base standard 10 in which is pivoted at 11 an operators control-element 12 which takes detail view of theoperators the form of a pedal, but which could, of

' Valve 19`and admit steam to the ejector 15,-v and as the piston 25 moves down it'will un` f' function of this re-action has already beenl with the inlet 22 to the ejector 15. The ejector 15 is connected by afflconduit 23 with the cylinder 14 and at 24 i'skshown the outlet connection of the ejector.

Within the cylinder 14 is a piston 25 having a piston rod 26 which is pivoted at 27 to the pedal 12. The piston 25 is pressedv upwards by a spring 28 and the space below the piston is in free communication with the atmosphere through the aperture 29. Intermediate its ends, the rod 26Yis cut away to provide a cam face 30 against which bears the end of the stem 31 of the valve 19. yThis valve is pressed towards its closing position by a spring 32 and is opened by the cam face 30 when the pedal 12 is depressed. The end of the stem 31 projects into a chamber 33 below the cylinder 14, which chamber has a. drainage outlet 34.

At the upper end communicating with lateral venting conduits 37. Between the perforation 36 and the conduits 37 a valve seat 38 is formed towards whichl a lvalve 39 is pressed by a spring 40. Projecting from the upper end of the rod. 26 or of the nut 41 upon it, is a boss 42 which lifts the valve 39 from its seat when' the piston 25 reaches theupper limit of its travel. The conduit 18 is so situated that it is never entirely closed bythe piston 25 and'thus will always'be in communication with the perforation 36.

In operation, to apply the brakes, the operator will depress the pedal 12 thereby drawing down the rod 26 rand piston 25. As the rod 26 moves down it will open the cover the end of the conduit 23 and place the latter in communication with the conduit 18. Thus the vacuum created by, the ejector 15 will extend from the conduit 23 to the braking system. This vacuum, however, will also tend to lift the piston'25 and thus will giveA the re-action upon the pedal 12\ to the operators push thereon. The

described. .Y

When braking is no 'longer required, the

operator withdraws his foot from the pedal 12 and it moves upwardly. In so doing the f j j valve 19 is permitted to close and the piston 25 first closes the end of the conduit 23 and subsequently opens the venting valve 39. Thus the vacuum is destroyed in the braking system and the latter eiiectively kshut olf from the ejector which may be of 1mportance if the latter happens tol become leaky. It

also prevents condensed steam 'beingdrawn back into the brake pipe when the steam valve closes.

4 of the cylinder 14 is-a" cap 35 which has a central perforationo36 'It is to be understood that the invention isf not limited to the pre/isc constructional de- .j

tails hereinbefore set I claim l 1. In a vacuum brakingsystem, the combination with the operators control-element, of\a piston-member other than the main braking piston, means for directly coupling the said control-element and piston-member together, and means whereby a face of the piston-member is exposed to the vacuumv in the system when brakingis taking place and the opposite face exposed to atmosphere, for the purpose specified.

2. In a vacuum braking system, the combination with an operators controlling leorth.

ver, of a piston-member other than the main braking piston, one face of which pist-onmember is exposed to atmosphere, a conduit opening towards thel other face and adapted to communicate with the vacuum chamber for themain brakingpistomand a rod directly coupling the controlling leverand the piston-member. i

3. In a vacuum braking system, the comb1nat1on with means for creatinga vacuum, a

conduit connecting said means with the main braking piston', a piston-member other than the main braking piston which is adapted to close said conduit, an operators controlelement, means for directly couplingvthe said control-element and the piston-member together and means whereby one 'face of said piston-member is exposed to atmosphere, the said piston-member being adapted to be moved into position to open the said conduit and thereby ex'pose its otherrfa'ce to the vacuum in the system when braking is taking place, for the purpose specified.

4. A vacuum braking system, comprising the combination with a source of pressure, 'an ejector, and a conduit leading to the main braking piston, from .which conduit air can be exhausted by the'ejector, of an operators control-element for the system, a pistonmember other than the main braking piston having one face exposed to the vacuum 1n the system whenbraking istaking place and the opposite face accesssible to thel atmosphere, means for directly coupling the said piston-member to the control-element, and means wohereby the said piston-member controls communication between the source of pressure and the ejector, and between the ejector and the, braking system.

5. A vacuum 'braking system,comprising the combination with a source of pressure,

"an ejector, and a conduit leading to the main braking piston from the ejector, of

an operators control-element for the system,

a piston-member lother than the main braking piston having one `face exposed to the vacuum in the system when braking is takj ing place and the op osite face accessible to the atmosphere and eing arranged to move into said conduit to close it, means for directly coupling the said piston-member to the control-element, a cam moving with said piston-member and a valve operated by said cam to control communication between the source of pressure and the ejector.

6. In a vacuum braking system, the combination with the operators control-element, of a piston-member other than the main braking piston, means for the said control-element and piston-member together, means whereby' a face of the piston member is exposed to the vacuum in the system when braking is taking place and the opposite face exposed to atmosphere, a venting valve for destroying the vacuum in the braking system, and means whereby said valve is opened by the piston-member when the latter reaches the position it occupies when braking is not taking place.

7. In a vacuum braking system, the combination with the operators control-element, of a piston-meinber other than the main braking piston, means for directly coupling the said control-element and piston-member together,- means whereby a face of the piston-member is exposed to the vacuum in the system when braking is taking place and the opposite face exposed to atmosphere, a Venting valve for destroying the vacuum in the braking system, means tending to close said valve, and an extension on the said piston-member adapted to open the valve when the piston-member reaches the position it occupies when braking isnot taking place.

8. In a vacuum braking system, the combination with means for creating a vacuum, a conduit connecting said means with the main braking-piston, a piston-member other directly coupling than the main braking piston which is adapted to close said conduit, an operators control-element, means for directly coupling the said control-element and the pistonmember together, one face of said pistonmember being exposed to atmosphere and thesaid piston-member being adapted to be moved into position to open the said conduit and thereby expose its opposite face to the vacuum in the system when braking is taking place, a venting valve for destroying the Vacuum in the braking system, and means whereby said valve is opened by the piston-member.

9. In a vacuum braking system, the combination with means for creating a vacuum, a conduit connecting said means main braking piston, a piston-member other than the main braking piston which is adapted to close said conduit,an operators control-element, means for directly coupling the said contro1-element and the pistonmember together, one face of said pistonmember being exposed to atmosphere and the said piston-member being adapted to be moved into position to open the said conduit and thereby expose its oppositey face `to the vacuum in the system when braking is taking place, a venting valve for destroying the vacuum inl the braking system, and means whereby the said piston member in returning to the position it occupies when braking said conduit between the main braking piston and the means for creating the vacuum, and subsequently opens the said venting valve and destroys the vacuum in the brak-` ing system.

In testimony whereof I alix my signature.

STEPHEN EVANS ALLEY.

is not taking place first closes the with the 

